1. Field of the Invention
The present invention relates to a display device such as a liquid crystal display device, and a method of driving the same, and more particularly to a display device having an electrostatic capacitance type touch sensor which a user touches with his/her finger, thereby making it possible to input information, and a method of driving the same.
2. Description of the Related Art
There is known a liquid crystal display device with a contact detector called a so-called touch panel (hereinafter referred to as “a touch sensor”). In this liquid crystal display device, the touch sensor is formed so as to be stacked on a liquid crystal panel, and various kinds of buttons are displayed as images on a liquid crystal display surface. Thus, information can be inputted with the various kinds of buttons displayed as images instead of using normal mechanical buttons. When this technique is applied to a miniature mobile device, dispositions of a display and buttons can be commonized. As a result, there is provided a superior merit such as scaling-up of a screen, space saving of a manipulation portion, and reduction of the number of parts or components. However, when the touch panel is provided in the liquid crystal panel, an entire liquid module is thickened.
In order to cope with this situation, for example, Japanese Patent Laid-Open No. 2008-9750 proposes a liquid crystal display element with a touch panel. This liquid crystal display element with a touch panel is such that a conductive film for the touch panel is provided between an observation side substrate of the liquid crystal display element, and a polarizing plate for observation disposed on an outer surface of the observation side substrate, and an electrostatic capacitance type touch panel is formed between the conductive film for the touch panel, and the outer surface of the polarizing plate by using the outer surface of the polarizing plate as a touch surface. In this case, this liquid crystal element with the touch panel is thinned.